Reference is made to U.S. patent application Ser. No. 09/503,573, filed Feb. 14, 2000, for CONTROL FOR DRIVE MOTORS FOR A SELF-PROPELLED MACHINE, the content of which is hereby incorporated in its entirety by reference.
The present invention relates to a mechanical motion alarm actuator that utilizes a single switch and an actuator on a multi valve pilot valve control and wherein the switch is engaged and opened in the neutral position of the pilot valve control only. This alarm actuator is particularly useful in signalling any movements of the vehicles or machines that are caused by movement of the pilot valve actuating system to warn of such movements. The actuator is illustratively disclosed in connection with earth working excavators which use pilot valve controls for controlling movement and steering of the frame of the excavator.
At the present time excavator motion alarms usually use at least two switches, one for each travel lever or travel linkage. The switches are normally open when the travel levers are in neutral, and when either or both of the levers are actuated, either one or both of the switches close, which activates the alarm. Since the upper structure of an excavator can be rotated 360xc2x0, a motion alarm is required to activate for any ground drive movement of the excavator, namely forward, reverse, and left or right turning movement, and is distinguished from a xe2x80x9cbackupxe2x80x9d alarm. An alarm should sound at any time when the excavator is moved along the ground, in that what might be forward movement at one time can be reverse at another time, when the cab has been rotated 180xc2x0 relative to the propelling tracks.
Joystick movement indicators have been advanced. U.S. Pat. No. 5,737,993 shows an electronic arrangement whereby a sensor senses the position of the joystick and generates an operator command signal that is in effect a velocity signal.
Various back-up alarms also have been utilized, which will sense the position of a transmission element, or sense a position of an actuator element, to provide a single signal when a unit is placed into reverse. Such reverse or back-up warnings are common on industrial equipment and large trucks.
Pilot valves that are operated by mechanical controllers are used on earth working excavators, and mounting a motion alarm switch and actuator to insure that the alarm is activated whenever the controller is moved from its neutral position has been difficult. Movement of individual control levers can be sensed, but that requires two switches, as previously explained.
The present invention relates to a motion alarm actuator that provides mechanical activation of the alarm in any working position of a multiposition, multifunction control. No warning is provided in a neutral position.
In the present invention a single switch is mounted adjacent a pilot actuator or control with the switch having a roller at the end of an actuator arm. The switch is operated by an actuator member on the pilot actuator, which preferably also has a roller engaging the switch roller in neutral position, and mounted so that movement of the actuator member as the pilot control member is moved to initiate a drive in any direction, will disengage from the switch roller. The switch closes to provide the alarm signal. The alarm switch is closed whenever the pilot control member moves from its neutral position. The roller on the actuator member that moves with the pilot control provides a smooth reengagement with the switch roller to cause the switch to be opened when the pilot valve control member moves back to its neutral position, without binding, and without bending of parts, using a very simplified mounting. The pilot control is disclosed as and will be described as a pilot valve control.